You’ve likely noticed a puddle that forms right on the outside edge of your roof. That puddle is from melted snowpack. Once it starts to freeze, the ice can actually make its way under the shingles, which will cause leaks and thousands of dollars in damage.

There are two big telltale signs you likely have an ice dam: you’ll see big icicles that form or you’ll see ice built-up in what’s called the roof’s “valleys” where the two slopes meet.

“That’s where you’ll have your problem occur, because all the snow that melts off this roof and that melts off that roof are all flowing to that single spot,” said Hoheisel.

Professional contractors can melt the ice using a high-pressure steam spray.

As for preventing the dam all together, you can do two things. One, make sure snow is off of your roof vents and two, make sure your attic insulation is up to par. It’s the warm air – after all – that’s responsible for the melting.

The bottom line is don’t be afraid to call for help – before it’s too late.

Hoheisel says older homes run into more problems because of poor attic insulation and ventilation. You can talk to a contractor about putting a vent in the attic.

Another tip: make sure you check to see if your homeowners insurance covers any of the repair costs.